Silver deposition on titanium oxide thin glass films for efficient visible light-induced photocatalytic removal of diphenhydramine and venlafaxine

The development of visible light-responsive metal-doped TiO2 for the treatment of water and wastewater has gained much attention. Herein, TiO2/Ag nanocatalyst thin films stabilized on glass was successfully obtained by a simple sol–gel method. The morphology, crystalline and functional structure, bandgap energy, and optical properties of synthesized TiO2/Ag were studied by XRD, FTIR, FESEM-EDX, and UV–Vis DRS analyses. The results showed that the size of most of the nanoparticles was between 20 and 40 nm. Besides, the red shift to the visible region and the reduction of bandgap energy to 2.7 eV were observed as a result of the modification of TiO2 by Ag. The diphenhydramine (DPH) and venlafaxine (VNF) photodegradation efficiency were studied using the TiO2/Ag/UV–Vis process with independent variables by the response surface methodology (RSM). The proposed RSM models with high R2 (0.996–0.997) confirmed a satisfactory correlation between the experimental results and predicted values. The RSM results showed the significant inhibitive effects of increasing antibiotic concentration on the removal efficiency, whereas the highest positive impacts on the degradation efficiency were obtained by increasing the irradiation time. More than 70% of drugs were removed under optimum conditions (20 mg/L of initial VNF (DPH) concentration, pH of 10 under 180 min illumination).